/// <summary>
/// Creates a negative acknowledgement message.
/// </summary>
/// <param name="request">The request message to use to create the response message.</param>
/// <param name="responseCode">The response code of the message.</param>
/// <param name="errCode">The error code of the message.</param>
/// <param name="errDescription">The error description of the message.</param>
/// <returns>Returns the created negative acknowledgement message instance.</returns>
public static IMessage CreateNack(IMessage request, string responseCode, string errCode, string errDescription)
{
MessageUtil.tracer.TraceEvent(TraceEventType.Warning, 0, $"NACK Condition : {errDescription}");
if (request.Version == "2.3.1")
{
var ack = new ACK();
var terser = new Terser(ack);
terser.Set("/MSA-1", responseCode);
terser.Set("/MSA-3", "Error occurred");
terser.Set("/MSA-6-1", errCode);
terser.Set("/MSA-6-2", errDescription);
UpdateMSH(terser, request);
return(ack);
}
else
{
var ack = new NHapi.Model.V25.Message.ACK();
var terser = new Terser(ack);
terser.Set("/MSA-1", responseCode);
UpdateMSH(terser, request);
terser.Set("/ERR-3-1", errCode);
terser.Set("/ERR-3-2", errDescription);
return(ack);
}
}
/// <summary>
/// Create NACK
/// </summary>
internal static IMessage CreateNack(IMessage request, string responseCode, string errCode, string errDescription, ISystemConfigurationService config)
{
System.Diagnostics.Trace.TraceWarning(String.Format("NACK Condition : {0}", errDescription));
if (request.Version == "2.3.1")
{
NHapi.Model.V231.Message.ACK ack = new NHapi.Model.V231.Message.ACK();
Terser terser = new Terser(ack);
terser.Set("/MSA-1", responseCode);
terser.Set("/MSA-3", "Error occurred");
terser.Set("/MSA-6-1", errCode);
terser.Set("/MSA-6-2", errDescription);
MessageUtil.UpdateMSH(terser, request, config);
return(ack);
}
else
{
NHapi.Model.V25.Message.ACK ack = new NHapi.Model.V25.Message.ACK();
Terser terser = new Terser(ack);
terser.Set("/MSA-1", responseCode);
MessageUtil.UpdateMSH(terser, request, config);
terser.Set("/ERR-3-1", errCode);
terser.Set("/ERR-3-2", errDescription);
return(ack);
}
}
/// <summary>
/// Receive and process message
/// </summary>
protected virtual void OnReceiveMessage(object client)
{
using (TcpClient tcpClient = client as TcpClient)
{
this.m_traceSource.TraceEvent(EventLevel.Verbose, "Accepted connection on {0} from {1}", this.m_listener.LocalEndpoint, tcpClient.Client.RemoteEndPoint);
NetworkStream stream = tcpClient.GetStream();
try
{
// Now read to a string
DateTime lastReceive = DateTime.Now;
while (DateTime.Now.Subtract(lastReceive) < this.m_timeout)
{
if (!stream.DataAvailable)
{
Thread.Sleep(10);
continue;
}
// Read LLP head byte
int llpByte = stream.ReadByte();
if (llpByte != START_TX) // first byte must be HT
{
throw new InvalidOperationException("Invalid LLP First Byte");
}
// Standard stream stuff, read until the stream is exhausted
StringBuilder messageData = new StringBuilder();
byte[] buffer = new byte[1024];
bool receivedEOF = false, scanForCr = false;
while (!receivedEOF)
{
if (DateTime.Now.Subtract(lastReceive) > this.m_timeout)
{
throw new TimeoutException("Data not received in the specified amount of time. Increase the timeout or check the network connection");
}
if (!stream.DataAvailable)
{
Thread.Sleep(10);
continue;
}
int br = stream.Read(buffer, 0, 1024);
messageData.Append(System.Text.Encoding.UTF8.GetString(buffer, 0, br));
// Need to check for CR?
if (scanForCr)
{
receivedEOF = buffer[0] == END_TXNL;
}
else
{
// Look for FS
int fsPos = Array.IndexOf(buffer, (byte)END_TX);
if (fsPos == -1) // not found
{
continue;
}
else if (fsPos < buffer.Length - 1) // more room to read
{
receivedEOF = buffer[fsPos + 1] == END_TXNL;
}
else
{
scanForCr = true; // Cannot check the end of message for CR because there is no more room in the message buffer
}
// so need to check on the next loop
}
}
// Use the nHAPI parser to process the data
Hl7MessageReceivedEventArgs messageArgs = null;
String originalVersion = null;
// Setup local and remote receive endpoint data for auditing
var localEp = tcpClient.Client.LocalEndPoint as IPEndPoint;
var remoteEp = tcpClient.Client.RemoteEndPoint as IPEndPoint;
Uri localEndpoint = new Uri(String.Format("llp://{0}:{1}", localEp.Address, localEp.Port));
Uri remoteEndpoint = new Uri(String.Format("llp://{0}:{1}", remoteEp.Address, remoteEp.Port));
foreach (var messagePart in messageData.ToString().Split((char)END_TX))
{
if (messagePart == "\r")
{
continue;
}
try
{
this.m_traceSource.TraceInfo("Received message from llp://{0}:{1} : {2}", remoteEp.Address, remoteEp.Port, messagePart);
// HACK: nHAPI doesn't like URLs ... Will fix this later
string messageString = messagePart.Replace("|URL|", "|ST|");
var message = MessageUtils.ParseMessage(messageString, out originalVersion);
messageArgs = new Hl7MessageReceivedEventArgs(message, localEndpoint, remoteEndpoint, DateTime.Now);
HL7OperationContext.Current = new HL7OperationContext(messageArgs);
// Call any bound event handlers that there is a message available
OnMessageReceived(messageArgs);
}
catch (Exception e)
{
this.m_traceSource.TraceError("Error processing HL7 message: {0}", e);
if (messageArgs != null)
{
var nack = new NHapi.Model.V25.Message.ACK();
nack.MSH.SetDefault(messageArgs.Message.GetStructure("MSH") as NHapi.Model.V25.Segment.MSH);
nack.MSA.AcknowledgmentCode.Value = "AE";
nack.MSA.TextMessage.Value = $"FATAL - {e.Message}";
nack.MSA.MessageControlID.Value = (messageArgs.Message.GetStructure("MSH") as NHapi.Model.V25.Segment.MSH).MessageControlID.Value;
messageArgs.Response = nack;
var icomps = PipeParser.Encode(messageArgs.Message.GetStructure("MSH") as NHapi.Base.Model.ISegment, new EncodingCharacters('|', "^~\\&")).Split('|');
var ocomps = PipeParser.Encode(messageArgs.Response.GetStructure("MSH") as NHapi.Base.Model.ISegment, new EncodingCharacters('|', "^~\\&")).Split('|');
AuditUtil.AuditNetworkRequestFailure(e, messageArgs.ReceiveEndpoint, Enumerable.Range(1, icomps.Length).ToDictionary(o => $"MSH-{o}", o => icomps[o - 1]), Enumerable.Range(1, icomps.Length).ToDictionary(o => $"MSH-{o}", o => ocomps[o - 1]));
}
else
{
AuditUtil.AuditNetworkRequestFailure(e, localEndpoint, new System.Collections.Specialized.NameValueCollection(), new System.Collections.Specialized.NameValueCollection());
}
}
finally
{
// Send the response back
using (MemoryStream memoryWriter = new MemoryStream())
{
using (StreamWriter streamWriter = new StreamWriter(memoryWriter))
{
memoryWriter.Write(new byte[] { START_TX }, 0, 1); // header
if (messageArgs != null && messageArgs.Response != null)
{
var strMessage = MessageUtils.EncodeMessage(messageArgs.Response, originalVersion);
this.m_traceSource.TraceInfo("Sending message to llp://{0} : {1}", tcpClient.Client.RemoteEndPoint, strMessage);
// Since nHAPI only emits a string we just send that along the stream
streamWriter.Write(strMessage);
streamWriter.Flush();
}
memoryWriter.Write(new byte[] { END_TX, END_TXNL }, 0, 2); // Finish the stream with FSCR
stream.Write(memoryWriter.ToArray(), 0, (int)memoryWriter.Position);
stream.Flush();
}
}
lastReceive = DateTime.Now; // Update the last receive time so the timeout function works
}
}
if (!stream.DataAvailable)
{
return;
}
}
}
catch (Exception e)
{
this.m_traceSource.TraceEvent(EventLevel.Error, e.ToString());
}
finally
{
stream.Close();
tcpClient.Close();
HL7OperationContext.Current = null;
}
}
}